The present disclosure relates to a vaporized fuel processing apparatus which has, in a path connecting a fuel tank and a canister, a closing valve that controls communication between the fuel tank and the canister.
A known vaporized fuel processing apparatus equipped with a closing valve has a problem in that, if the fuel tank is in a sealed state due to closing of the closing valve, and the internal pressure of the fuel tank is high, vaporized fuel that has accumulated in the fuel tank may be dissipated into the atmosphere via a refueling port when the refueling cap of the fuel tank is opened for refueling. In view of this, according to the invention disclosed in Japanese Laid-Open Patent Publication No. 2011-169276, if the fuel tank internal pressure is high at the time of refueling, the closing valve is opened to reduce the fuel tank internal pressure before opening the refueling cap. Further, if the speed at which the fuel tank internal pressure is reduced is high, a float valve inside the fuel tank may be closed to cause a problem in that a reduction in the internal pressure is not possible; in view of this, a control is performed to suppress the opening degree of the closing valve for suppressing the reduction speed.